Partial support is requested for the symposium "Aging in the terminally differentiated cell: Development, Aging, and Death of the Neuron" which will be offered by the Biological Sciences Section of the Gerontological Society of America at its 40th Annual Meeting in Washington, D.C. in November 1987. The funds will be used to support non-member invited speakers; GSA members will provide their their own funds. The symposium will focus on NEW DISCOVERIES IN THE MOLECULAR AND DEVELOPMENTAL BIOLOGY OF POST-MITOTIC CELLS, THE NEURON IN PARTICULAR, AND THEIR IMPLICATIONS FOR SENESCENCE AND PATHOLOGY. The symposium is divided into two sections and five sessions: Section 1: CHEMICAL COMMUNICATIONS WHICH DETERMINE CELL ACTIVITY AND BEHAVIOR. (a) The communication that establishes the path of cell differentiation and neuronal specificity, including the recent discoveries of cell-surface communications as guiding the growth of axons and the time-dependent appearance and recognition of surface antigens. (b) Signals used in the life-long maintenance of cells (polypeptide growth factors, especially nerve growth factor). Section 2: THE NORMAL AND PATHOLOGICAL LOSS OF CELLS. (c) Mechanisms of cell death, in particular neuronal, cardiac, and developmental cell involution and death, concluding with consideration of the relationship between developmental and pathological loss of cells. (d) Clinical implications such as degenerative neural diseases and animal models for neural degeneration. (e) Possibilities of repair, including anatomical and behavioral neuronal plasticity, regeneration, and maintenance of muscle mass and an overview of the role of mitotic and post- mitotic cells in aging. The participants in the symposium represent a balance of scientists with general expertise in neurobiology and society members with expertise in gerontological aspects of neurobiology. They should be able to share ideas and to provide provocative interactions of broad interest. Negotiations are planned to publish the reports in a collected work such as a single issue of the Journal of Gerontology, Biological Sciences section.